Is this for real?

The party confirmed that plans to legalise cannabis would be in its manifesto and will be brought forward if they gain power.

How would it work?

The Lib Dems will commit to creating a legal market for the production and sale of weed, so it can be taxed and sold on the high street in licensed shops.

Cannabis would only be sold to people over 18 and sales would be strictly regulated under the new proposals, which could generate up to £1 billion per year in tax revenues, the party predicts.

More will become clear when the Lib Dem manifesto is released over the coming days.

Where has this come from?

The Lib Dems have long campaigned to legalise the drug, with former health minister Norman Lamb attempting to bring in a Bill last year to tackle what he called “a catastrophic failure” of the war on drugs.

The party’s pledge makes it one of the first political parties to fight an election on a ticket of relaxing drug laws.

Lib Dem candidate Julian Huppert, who is standing in Cambridge, said the current approach was “a disaster”, which was causing significant mental and physical harm for young people.

He said: “There are no age checks, and no controls on quality or strength. ‘Skunk’ is widespread and the only ID you need to buy it is a £20 note.

“Successive governments have ceded total control of a significant public health problem to organised crime.

“The honest and pragmatic response is to take responsibility for this situation and regulate the market.”

Does this extend to other drugs?

Lib Dem aides acknowledged to Buzzfeed that this could develop into a pledge to legalise and regulate recreational drugs like MDMA, but at this election cannabis is the only drug they propose legalising.

What are the benefits of legalisation?

Legalising drugs takes power and money away from the black market, advocates say, and in turn ensures safer and more consistent strains of cannabis.

North Norfolk Lib Dem candidate Lamb said: “We are criminalising young people, people have no idea what they are buying so there is a major health risk.”

What is the law currently?

People in possession of cannabis currently face up to five years in prison, while the class B drug carries a 14-year sentence for supplying.